KINGSTON >> Work will be done this week at the Washington Avenue sinkhole to plug leaks in a sanitary sewer line beneath a 100-year-old stormwater tunnel, according to City Engineer Ralph Swenson.

Swenson said the leaks are not new. They were detailed in a video taken a few months ago.

He said workers will descend into the tunnel to do the grouting work to plug the leaks and that more video camera investigation will be done at the site.

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“(The video) from a few months ago was good enough to identify these leaks,” Swenson said.

The engineer said that the latest work should be completed by the end of the week and that this round of sinkhole repair will cost about $150,000, funding already approved by the Common Council and Mayor Shayne Gallo.

City officials still are awaiting an additional opinion about how best to stabilize soil around the sinkhole.

Swenson told the Common Council’s Finance/Economic Development Committee in December that he was not prepared to make a recommendation on either of two opinions from consulting engineers about how the stabilization work.

The stabilization is intended to keep the century-old underground tunnel at the site from sagging. Leaks in that tunnel are believed to have caused the sinkhole, which opened up nearly three years ago on Washington Avenue near Linderman Avenue. Washington Avenue from Linderman to The Boulevard has been closed to traffic ever since.

The engineering firm Brierley Associates has recommended a portion of the tunnel be encased in a cement-like material, a shaft atop the tunnel be closed off and another be built along its side. It also said efforts should be made to close off voids in soil around the tunnel.

Additionally, Brierley said in a letter to city officials, a “load transfer platform (should be constructed) to distribute traffic loads from the pavement to the rammed aggregate piers.”

Mueser Rutledge Consulting Engineers said an underground arch — 50 feet high, 175 feet long and weighing about 10,000 tons — should be constructed around the sagging tunnel.

The Common Council will have to authorize spending an additional $2 million if either project is approved.

Lawmakers already have authorized spending about $4 million on sinkhole-related work.

About the Author

Paul Kirby is a reporter for the Freeman, covering Kingston politics. He has been at the Freeman since August 1996. Reach the author at pkirby@freemanonline.com
or follow Paul on Twitter: @PaulatFreeman.